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Atomic symbol: Ta |
Atomic number: 73 |
Atomic weight: 180.947 |
Atomic volume: 10.90 cm3/mol |
Density: 16.6 g/cm3 |
Period Number: 6 |
Group number: 5 |
Group name: Trans. Met. |
Element classification: Metal |
Phase at room temperature: Solid |
Melting Point: 3269.2 K |
Boiling point: 5807 K |
Heat of fusion: 31.60 kJ/mol |
Heat of vaporization: 743.0 kJ/mol |
Ionization Energy: 7.89 eV |
1st ionization energy: 761 kJ/mole |
2nd ionization energy: kJ/mole |
3rd ionization energy: kJ/mole |
Electronegativity: 1.5 |
Electron affinity: 31.1 kJ/mole |
Specific heat: 0.14 J/gK |
Heat atomization: 782 kJ/mole atoms |
Shells: 2,8,18,32,11,2 |
Electron Shell Configuration: [Xe] 4f14 5d3 6s2 |
Minimum oxidation number: -1 |
Maximum oxidation number: 5 |
Minimum common oxidation number: 0 |
Maximum common oxidation no: 5 |
Appearance & Characteristics |
Structure:: bcc: body-centered cubic |
Color: gray |
Hardness: mohs |
Toxicity: ? |
Characteristics: hard, inert at <100 deg.C |
Uses: surg. implants,heat exch. |
Reaction with air: none |
Reaction with 6M HCl: none |
Reaction with 15M HNO3: none |
Reaction with 6M NaOH: none |
Number of isotopes: 2 |
Oxide(s): TaO2 Ta2O5 |
Hydride(s): TaH |
Chloride(s): TaCl3 TaCl4 TaCl5 |
Atomic Radius: 146 pm |
Ionic radius (1- ion): pm |
Ionic radius (1+ ion): pm |
Ionic radius (2- ion): pm |
Ionic radius (2+ ion): pm |
Ionic radius (3+ ion): 86 pm |
Thermal conductivity: 57.5 J/m-sec-deg |
Electrical conductivity: 80.321 1/mohm-cm |
Polarizability: 13.1 A^3 |
Source: Tantalite (oxide) |
Relative abundance solar system: -1.684 log |
Abundance earth's crust: 0.3 log |
Estimated crustal abundance: 2.0 milligrams per kilogram |
Estimated oceanic abundance: 2×10-6 milligrams per liter |
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(Gr. Tantalos: mythological character, father of Niobe) Discovered in 1802 by Ekeberg, but many chemists thought niobium and tantalum were identical elements until Rowe in 1844, and Marignac, in 1866, showed that niobic and tantalic acids were two different acids. The early investigators only isolated the impure metal. The first relatively pure ductile tantalum was produced by von Bolton in 1903. Tantalum occurs principally in the mineral columbite-tantalite. |
Tantalum ores are found in Australia, Brazil, Mozambique, Thailand, Portugal, Nigeria, Zaire, and Canada. |
Tantalum is a gray, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals such as aluminum. Tantalum is almost completely immune to chemical attack at temperatures below 150oC, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulfur trioxide. Alkalis attack it only slowly. At high temperatures, tantalum becomes much more reactive. The element has a melting point exceeded only by tungsten and rhenium. Tantalum is used to make a variety of alloys with desirable properties such as high melting point, high strength, good ductility, etc. Tantalum has a good "gettering" ability at high temperatures, and tantalum oxide films are stable and have good rectifying and dielectric properties. |
Scientists at Los Alamos have produced a tantalum carbide graphite composite material, which is said to be one of the hardest materials ever made. The compound has a melting point of 37380C. Tantalum is used to make electrolytic capacitors and vacuum furnace parts, which account for about 60% of its use. The metal is also widely used to fabricate chemical process equipment, nuclear reactors, aircraft, and missile parts. Tantalum is completely immune to body liquids and is a nonirritating material. It has, therefore, found wide use in making surgical appliances. Tantalum oxide is used to make special glass with high index of refraction for camera lenses. The metal has many other uses. |
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SEKOM Handelsges.m.b.H.... |
Our company is a private firm founded in 1990 with aim to develop export and import with Russia. We do promote EU industrial and consumer goods in Russia and strongly support marketing of Russian and CIS industrial products and services.
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